Sounds like a decent upgrade. (Score 1)

If I'm not entirely off my mark, the idea of solar sails has been around for a long time, and I actually had a friend in highschool who did a nationally recognoized science fair project concerning materials for and propulsion from solar sails. A few microns thick is all it needs to be, and it's still quite tough, think super-thin garbage bags, the sail material has similar tensile properties. A 60MW microwave beam seems like it would make an awful nice weapon, but I imagine if it were space based, it could be somewhat less powerful to achieve a similar effect on the spacecraft. That and the fact that the power is spread over the area of a 100m diameter circle... 50*50*Pi comes out to around 7850 square meters, which means you get 7.643kW per meter squared... about 710W per square foot for those of us who don't like metric. I'm not an expert, but 710W/sqft sounds like less power than the microwave in my kitchen can put out.